I don't understand why you say that the alignment with the galactic plane is and "inexact concept" by a "million years" margin, the recent post of Dr. Postman shows very *precise* definitions of what it means,.....................................We were talking about two different things.

In the Dr. Postman post, he was explaining precession of the equinoxes or the Earth's wobble which does cycle every 26,000 years.

I was referring to the wave-like motion of the solar system "bobbing" up and down through the galactic plane. This takes millions of years and would be expected to bring a higher density of energy and objects in or near our solar system. With this event, an alignment with the galactic plane would not be precise.

Take a look at the two illustrations in the link and see if we're on the same page:

was part of the explanation of what was going to happen. But looks like the crossing happened some 3 million years ago, then we should be now getting away from the galactic plane not closer!

Thanks for the link and explanation.

I'd like to notice, in connection with my attempt to understand the Ice Ages, that 3 million years ago our planet Earth was much hotter than it is today, something like 5 degrees C above our present levels, see for example the following [link to muller.lbl.gov]

Then, if we assume some connection between the passage across the galactic plane (GP) and an increasing warming of the solar system we could probably conclude that the more it got away from that plane the cooler it would be.

The 10-20 kyr of interglacials and 80-90 kyr of full glacial periods could perhaps be explained by some kind of oscillation in the interstellar plasma density that the solar system would encounter as it gets away from the GP.

Regarding 2012, my intuition still tells me that "something" very important is about to happen, but I agree that if we're going to speculate about it it's better to do so based on verifiable facts.